Improvement of Power Quality in Distribution System with Incorporation of Distributed Generation Using Ladder Load Flow Method

Distributed Generation (DG) is one of the adopted methods for improving electricity power demand of distribution systems which is more economical than building additional generation facilities. It can be in form of renewable energies, such as wind, mini-hydro and photovoltaic system or in the form of fuel-based system. Installing these generators in order to improve the power quality in distribution system requires an enhanced power load flow method to ensure the best possible placement. This paper presentsimprovement of power quality in distribution system with incorporation of DG using ladder load flow method. DG was incorporated into existing ladder load flow method to form a new equation for power flow analysis. Two set of equations were solved simultaneously using Ladder load flow iteration methods without and with incorporation of DG and simulation was carried out with MATLAB 7.9.0529 (R2012b) version by developing a Graphic User Interface (GUI) model using SIMULINK blocks. The model wasvalidated on standard IEEE 13-bus and 25-bus distribution test feeders for computation of active and reactive power. For 13-bus system, the results showed thattotal active power without DG was 0.8595 p.u. and 3.6925 p.u. with DG which indicate an increase in active power of 2.833 p.u (i.e 76.7% increase) while, the reactive power without DG was 0.5062 p.u. and 1.6960 p.u having installed DG (reactive power increase of 1.1898 p.u, i.e. 70% increase). For 25-bus system, total active power without DG was 3.3479 p.u. and 8.6888 p.u. with incorporation of DG which shows an increase in active power of 5.3409 p.u, i.e. 61.5% increase whilethe reactive power without DG was 2.0456 p.u. and 4.5817 p.u with DG (reactive power increase of 2.5361 p.u, which is 55.4% increase). The results revealed an improvement in power quality of the system after incorporation of DG into the distribution system which is in agreement with the experimental results, thus confirming the reliability of the model. The work provides an enhanced DG improvement model for power quality of electrical distribution system.